JP2023504664A - Driveline system for electric vehicle and method for cooling driveline system - Google Patents

Abstract

The present disclosure relates to driveline systems for electric vehicles. The drivetrain system comprises an electric motor comprising a rotor and a stator, a power inverter configured to supply electrical energy to the stator, and a speed reducer comprising a transmission shaft configured to receive the torque provided by the rotor. and wherein the electric motor, power inverter and speed reducer are integrated as a driveline assembly. The driveline system comprises a cooling circuit configured to flow coolant and distribute the coolant throughout the driveline assembly, the cooling channel disposed within the power inverter, the cooling channel flowing from the cooling circuit. a cooling circuit comprising a coolant retention section for retaining coolant of the cooling medium, an inlet for receiving the coolant, and an outlet for discharging the coolant; The present disclosure also relates to a method of cooling a drivetrain system for an electric vehicle.

Description

Embodiments of the present disclosure generally relate to driveline systems for electric vehicles and methods of cooling driveline systems.

Designing and manufacturing vehicles with good fuel economy and low emissions has become a significant trend. This trend is driven by environmental concerns as well as rising fuel costs. At the forefront of this trend are BEVs (battery electric vehicles), HEVs (hybrid electric vehicles), PHEVs (plug-in hybrid electric vehicles), EVs with range extenders, FCECs (fuel cell electric vehicles) and other relatively efficient vehicles. It is the development of an electric vehicle that combines an internal combustion engine and an electric drive motor. Electric vehicles may include heat-generating components, particularly driveline systems. Excessive heat generation can cause component degradation or damage.

Therefore, it would be desirable if an improved cooling design for driveline systems for electric vehicles could be provided, at least in a simple configuration, with high efficiency and low cost.

Aspects and advantages of the invention may be set forth in part in the description that follows, or may be apparent from the description, or may be learned through practice of the invention.

According to one aspect disclosed herein, a driveline system for an electric vehicle is provided. The drive train system comprises an electric motor comprising a rotor and a stator, a power inverter configured to supply electrical energy to the stator, and a speed reducer comprising a transmission shaft configured to receive the torque provided by the rotor. and wherein the electric motor, power inverter and speed reducer are integrated as a drivetrain assembly. The driveline system further comprises a cooling circuit in communication with the driveline assembly and configured to flow a coolant and distribute the coolant throughout the driveline assembly, the cooling circuit being configured to cool a cooling medium disposed within the power inverter. A cooling channel comprising a coolant retention section for retaining coolant from the cooling circuit, an inlet for receiving the coolant, and an outlet for discharging the coolant.

In one embodiment, the drive train system further comprises a mechanical pump component that connects to the cooling circuit and is driven by the transmission shaft to transfer the coolant to the cooling channel.

In one embodiment, the mechanical pump component is located on the same side as the electric motor or on a separate side of the reducer from the electric motor.

In one embodiment, a supplemental heat transfer element is provided within the cooling channel. Auxiliary heat transfer elements comprise at least one spike, extruded wall, or a combination thereof.

In one embodiment, the thermal mass is provided with an electric motor, a speed reducer, or both, and the power inverter benefits from the thermal mass by being mechanically attached to the electric motor, the speed reducer, or both. Benefits dissipate heat therein through coolant retained in cooling channels and auxiliary heat transfer elements therein which further increase heat transfer to the coolant retaining section and thermal mass. Let

In one embodiment, cooling fins are provided on the outer surface of the electric motor, the reducer, or both the electric motor and the reducer, and the power inverter is mechanically attached to the electric motor, or the reducer, or both. benefits from the cooling fins and transfers heat through the coolant held in the cooling channels and auxiliary heat transfer elements therein which further increase heat transfer to the coolant holding section and cooling fins. dissipate to

In one embodiment, the cooling channel is configured as a loop formed along the inner perimeter of the power inverter, with the inlet and outlet located at the upper end of the cooling channel in the gravitational orientation.

In an alternative embodiment, the cooling channel is configured as a serpentine shaped channel within the housing space of the power inverter.

In an alternative embodiment, the cooling channel is configured as a spiral-shaped channel within the housing space of the power inverter.

In an alternative embodiment, the cooling channels are configured as Z-shaped channels within the housing space of the power inverter.

According to another aspect disclosed herein, a method is provided for cooling a driveline system for an electric vehicle that includes a driveline assembly integrated with an electric motor, a power inverter, and a speed reducer. The method includes providing a cooling circuit configured to flow coolant and distribute the coolant throughout the driveline assembly; providing the cooling circuit with a cooling channel disposed within the power inverter; and further providing a coolant holding section for holding coolant.

In one embodiment, the method includes providing a mechanical pump component in connection with the cooling circuit, the mechanical pump component being driven by a transmission shaft of one of the driveline assemblies to transfer coolant to the cooling channel. Prepare more.

In one embodiment, the method further comprises providing a supplemental heat transfer element within the cooling channel to facilitate heat treatment from the power inverter. Auxiliary heat transfer elements comprise at least one spike, extruded wall, or a combination thereof.

In one embodiment, the method further comprises providing the thermal mass with an electric motor, a speed reducer, or both, wherein the power inverter is mechanically attached to the electric motor, the speed reducer, or both. through the coolant retained in the cooling channels of the inverter and auxiliary heat transfer elements therein which further increase heat transfer to the coolant retention section and the thermal mass, benefiting from the thermal mass by Dissipate heat inside it.

In one embodiment, the method further comprises providing cooling fins on the outer surface of the electric motor, the speed reducer, or both the electric motor and the speed reducer, wherein the power inverter is installed in the electric motor, the speed reducer, or both. Benefiting from the cooling fins by being mechanically attached, the coolant retained in the cooling channels and auxiliary heat transfer elements therein further increases heat transfer to the coolant retention section and cooling fins. through which heat is dissipated into it.

In one embodiment, the method comprises forming the cooling channel as a loop along the inner perimeter of the power inverter, and locating the inlet and outlet of the cooling channel at the upper end of the cooling channel in a gravitational orientation. Prepare more.

In an alternative embodiment, the method further comprises forming the cooling channel as a serpentine shaped channel within the receiving space of the power inverter.

In an alternative embodiment, the method further comprises forming the cooling channel as a spiral-shaped channel within the receiving space of the power inverter.

In an alternative embodiment, the method further comprises forming the cooling channels as Z-shaped channels within the receiving space of the power inverter.

These and other features, aspects, and advantages of the present disclosure will become better understood with reference to the following detailed description. The accompanying drawings, which are incorporated in and form a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

A complete and effective disclosure of the invention, including its best mode, directed to those skilled in the art is set forth in the specification with reference to the accompanying drawings.

1 is a schematic diagram of a drive train system according to an exemplary aspect of the present disclosure; FIG. FIG. 2 is a schematic diagram of a drivetrain system in accordance with another exemplary aspect of the present disclosure; FIG. 3 is a schematic diagram of a power inverter of a drivetrain system in accordance with an exemplary aspect of the present disclosure; 4 is a schematic diagram of one exemplary cooling channel of the power inverter shown in FIG. 3; FIG. 5 is a schematic diagram of another exemplary cooling channel of the power inverter shown in FIG. 3; FIG. FIG. 6 is a schematic diagram of another exemplary cooling channel of the power inverter of the present disclosure; FIG. 7 is a schematic diagram of another exemplary cooling channel of the power inverter of the present disclosure; FIG. 8 is a schematic diagram of another exemplary cooling channel of the power inverter of the present disclosure; FIG. 9 shows one exemplary power inverter with the thermal mass and cooling channels of FIG. FIG. 10 shows one exemplary power inverter with cooling fins and cooling channels of FIG. FIG. 11 shows another exemplary power inverter with thermal mass and the cooling channel of FIG. 8 with spikes. FIG. 12 is a flow diagram of a method of cooling a driveline system according to exemplary aspects of the present disclosure;

Embodiments of the invention will now be described in detail. One or more examples of the invention are illustrated in the accompanying drawings. Numerical and letter designations are used in the detailed description to refer to features in the drawings. Similar or similar designations in the drawings and description are used to refer to similar or similar parts of the invention. As used herein, the terms “a,” “an,” and “the” are intended to mean the presence of one or more elements, unless the context clearly dictates otherwise. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements. The terms "first" and "second" may be used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of individual components.

Referring to the drawings, like numerals refer to like elements throughout. 1 and 2 illustrate driveline systems 101, 102 according to embodiments of the present disclosure. More specifically, for the embodiment of FIG. 1 , driveline system 101 comprises driveline assembly 1 . The driveline assembly 1 is integral with a power inverter 3 (shown in FIG. 3), an electric motor 2 and a speed reducer 4 . The illustrated driveline assembly 1 is therefore a single unit.

The electric motor 2 can be a synchronous motor or an asynchronous motor. If it is a synchronous motor, it may include a wound rotor or a permanent magnet motor. The nominal power supplied by the electric motor can be 10 KW to 60 KW, for example in the order of 15 KW, or up to 800 V for higher powers, for a nominal supply voltage of 48 V to 350 V. In the case of an electric motor suitable for high voltage supply, the nominal power supplied by this electric motor may be 60 KW. In the illustrated embodiment, the electric motor 2 is a synchronous motor with permanent magnets and provides a nominal power of 10 KW to 60 KW. Electric motor 2 may include a stator with three-phase windings, or a combination of two three-phase windings or five-phase windings.

A speed reducer 4 is coupled to the electric motor 2 . The speed reducer 4 can convert the high speed and low torque of the electric motor to low speed and high torque. The speed reducer 4 may comprise two or more gears. One of the gears is driven, for example, by an electric motor 2 for increasing torque via deceleration. The reducer 4 may further comprise a transmission shaft 41, ie an intermediate shaft. The transmission shaft 41 comprises a driving gear driven by one transmission shaft (not shown) of an electric motor and another gear of large diameter coupled to a driven mechanical load (not shown, for example a wheel shaft of a vehicle). is connected with

In the illustrated embodiment, the electric motor 2 and the speed reducer 4 are designed to have a high heat capacity. A power inverter 3 (shown in FIG. 3) is connected by wires to the electric motor 2 and mechanically to the wall of the electric motor 2 or the wall of the reducer 4 or to both walls of the electric motor 2 and the reducer 4. installed. Power inverter 3 converts direct current (“DC”) supplied by an electrical energy storage unit (not shown) having electrical energy at a nominal voltage into alternating current (“AC”) used by electric motor 2 . Power inverter 3 may be, but is not limited to, a field effect transistor (“FET”), a metal oxide semiconductor field effect transistor (“MOSFET”) or an insulated gate bipolar transistor (“IGBT”). If the nominal power supply is 48V, power inverter 3 may be a MOSFET transistor. For supply voltages corresponding to high voltages, the power inverter 3 may be an IGBT.

With reference to FIGS. 1 and 2, the electric motor 2 is housed in a first housing 11 and the speed reducer 4 is housed in a second housing 12 . The first housing 11 and the second housing 12 may be integral or may be formed by assembling sub-parts of the housing together. The first housing 11 and the second housing 12 can be rigidly fixed to each other, for example by screws. Here, a sealing wall is provided between the first housing 11 and the second housing 12 .

Cooling fins 91 , 92 are provided to dissipate heat towards the exterior of the driveline assembly 1 . Cooling fins 91 and 92 are supported by the outer surfaces of first housing 11 and second housing 12 . These cooling fins 91 and 92 are made integrally with the first housing 11 and the second housing 12, for example. These cooling fins 91, 92 allow the outer surfaces of the first housing 11 and the second housing 12 to be increased, so that heat is dissipated to the outside of the drive train assembly 1 through the first housing 11 and the second housing 12. encourages people to be The entire outer surface of the first housing 11 and the entire outer surface of the second housing 12 may support cooling fins 91 and 92 . The cooling fins 91, 92 may be arranged in rows. There may be a constant or non-constant pitch between two adjacent rows. These columns may or may not all have the same orientation. The same fins can extend first towards the first housing 11 and then towards the second housing 12 if desired.

For the illustrated embodiment, a coolant flowing cooling circuit 5 is provided to distribute the coolant throughout the driveline assembly 1 . The coolant flowing through the cooling circuit 5 can be, for example, oil, water or an aqueous coolant.

Furthermore, in the illustrated embodiment, a mechanical pump component 6 is provided within the cooling circuit 5 . Mechanical pump component 6 may be a gerotor pump that may facilitate coolant flow through cooling circuit 5 . Furthermore, the mechanical pump part 6 is connected with the driveline assembly 1 and transports coolant to the driveline assembly, in particular to the power inverter 3, via one section 51 provided by the cooling circuit 5. , and is arranged to withdraw coolant from the drive train assembly, in particular from the reducer 4 , via another section 52 provided by the cooling circuit 5 . Sections 51 , 52 are located outside driveline assembly 1 . By using a mechanical pumping component 6, particularly with a gerotor pump, the coolant that is transported and flows in section 51 towards the drive train assembly provides a large constant delivery volume and high pressure. As shown in FIG. 1, the mechanical pump part 6 is mechanically connected to one end of the transmission shaft 41 so that the mechanical pump part 6 can be driven by mechanical power from the rotating shaft. The mechanical power generated by the rotating shaft can be fully utilized, as well as an additional source of power for driving pumps arranged in the cooling circuit to transport coolant (e.g. electrical power for driving electric pumps). ) is not required. Thus, eliminating a dedicated motor can save energy, lower costs, and reduce space.

However, it should be further understood that the example system 101 described herein is exemplary only. In some exemplary embodiments, the mechanical pump component 6 is mounted on the transmission shaft 41 to better utilize the rotational forces of the shaft within the driveline assembly 1, otherwise the assembly and as required. It may be mechanically connected to another end (eg, exemplary system 102 shown in FIG. 2).

Referring to FIG. 3, FIG. 3 shows a power inverter 3 of a drive train system according to one embodiment of the present disclosure. As shown in FIG. 3, a longitudinal orientation L corresponding to the axis of the power inverter 3, a transverse orientation T and a vertical orientation V corresponding to the gravitational orientation are defined. In the illustrated embodiment cooling channels 33 are provided by the cooling circuit 5 . Furthermore, the cooling channel 33 comprises an inlet 31 for receiving coolant from the mechanical pump component 6 and an outlet 32 for discharging the coolant. The cooling channel 33 is also provided with a coolant retention section 35 so that coolant is present in the cooling channel whether or not the mechanical pump component 6 is activated. Therefore, the cooling channel 33 can always be kept cool by the coolant flowing or remaining in the cooling channel 33 under the action of gravity.

In particular, as shown in FIGS. 3-5, the cooling channel 33 located within the radial surface of the power inverter 3 and formed along the inner peripheral edge of the power inverter is essentially an annular loop. The inlet 31 and outlet 32 are located at the upper ends of the cooling channels 33, 331 in the gravitational orientation. The inlet 31 and outlet 32 may also be arranged in a horizontal plane or there may be some height difference. In addition, coolant retaining sections 35, 351 are formed below cooling channels 33, 331 along the gravitational orientation. Due to the high thermal weight of the reducer and/or the electric motor, and the residual coolant that ensures heat transfer, the inverter continues to operate even when the mechanical pump system is at rest or operating at very low flow rates. can be cooled.

During operation of a mechanical pump component 6 such as a gerotor pump, a certain amount of coolant may be transferred from the gerotor pump to the cooling channels 33 , 331 within the power converter 3 . Specifically, coolant enters the cooling channel via inlet 31 , flows through the cooling channel, and exits the cooling channel via outlet 32 . Heat from the power inverter 3 is thus dissipated by the flow of coolant. When the rotating shaft to which the gerotor pump 6 is mechanically connected, ie the transmission shaft 41, comes to a standstill, coolant will remain in the coolant holding sections 35,351 of the cooling channels 33,331. This allows the remaining coolant to absorb heat by itself and transfer heat to the thermal mass, thereby keeping the power converter 3 cool.

4 and 5, these figures show different exemplary cooling channels 33,331. Auxiliary heat transfer elements are provided within the cooling channels 33 , 331 . This provides additional heat dissipation to the high heat capacity components, namely the speed reducer and the electric motor, even when the gerotor pump is running at low speed or at rest, for example. As illustrated in the embodiments, the supplemental heat transfer element is a plurality of metal spikes 34 as shown in FIG. 5 or extruded walls 341 as shown in FIG. 6 or a combination of spikes 34 and extruded walls 341. obtain. The auxiliary heat transfer element is made of a thermal material such as aluminum.

Referring to FIG. 6, another exemplary cooling channel 332 is shown. The cooling channel 332 is designed as a spiral shape. An inlet 312 is provided in the center of the shape and an outlet 322 is provided at the outer edge of the shape. A coolant retention section 352 is formed between inlet 312 and outlet 322 .

Referring to FIG. 7, another exemplary cooling channel 333 is shown. Cooling channel 333 is designed as a meandering shape. An inlet 313 is provided at the bottom of the shape and an outlet 323 is provided at the top of the shape. A coolant retention section 353 is formed between inlet 313 and outlet 323 .

Referring to FIG. 8, another exemplary cooling channel 334 is shown. The cooling channel 334 is designed as a Z-shape in the radial plane. Both inlet 314 and outlet 324 are provided at the top of the shape. A coolant retention section 354 is formed at the bottom of the shape.

However, it should be understood that the exemplary cooling channels 33, 331, 332, 333, 334 described herein are for illustration only. In addition to these shapes shown, the cooling channels are capable of retaining coolant and having minimal air inside, even when the coolant pump has a very low flow rate. Other shapes should be included.

9 and 10, the power inverter 3 containing cooling channels, such as the exemplary cooling channel 334 shown in FIG. Both motor l2 and reducer 4 can be contacted. Alternatively, the exemplary cooling channels 334 may contact cooling fins 91 , 92 located on the outer surface of the electric motor 2 or the speed reducer 4 or both the electric motor 2 and the speed reducer 4 . This configuration allows the coolant remaining in the cooling channel 334 to ensure heat transfer from the power inverter 3 . Additionally, heat from the power inverter 3 can be further dissipated by large thermal masses or cooling fins.

Referring to FIG. 11, a plurality of auxiliary cooling elements, such as spikes 34, are provided, such as exemplary Z-shaped cooling channels 334, for additional heat dissipation to large thermal masses (as shown) or cooling fins. provided in the cooling channels. The distance d between the spike and the surface of the cooling channel facing the thermal mass or cooling fins should be minimized. This will increase the heat dissipation area and provide a higher heat transfer effect.

Referring to FIG. 12, a flow diagram of an exemplary method 200 of cooling a driveline system is shown in accordance with exemplary aspects of the present disclosure. For example, exemplary method 200 may be used to cool exemplary driveline systems 101, 102 described above with reference to FIGS.

The exemplary method 200 includes providing 201 a cooling circuit connected to the driveline assembly, the cooling circuit configured to flow coolant to distribute the coolant throughout the driveline assembly. . The driveline assembly is integrated with an electric motor, power inverter and speed reducer.

The exemplary method 200 includes providing a cooling circuit with a cooling channel located inside the power inverter and further providing a coolant holding section in the cooling channel to provide a thermal mass, such as a motor and/or reducer, or a motor. and/or maintaining heat dissipation to cooling fins provided by the outer surface of the reducer to enable heat removal from the power inverter.

Subsequently, the exemplary method 200 includes providing 203 at least one spike, extruded wall, or combination thereof within the cooling channel to facilitate heat dissipation from the power inverter.

Further, the exemplary method 200 forms the cooling channel as a loop along the inner perimeter of the power inverter, with the cooling channel inlet and outlet located at the top of the cooling channel in a gravity orientation, or the cooling channel Forming 204 as a serpentine-shaped channel, a spiral-shaped channel, or a Z-shaped channel within the receiving space. The shape of the cooling channel and the location of the inlet and outlet of the cooling channel assist in forming a coolant retention section within the cooling channel.

Furthermore, the exemplary method 200 includes providing 205 a mechanical pump component connected to the cooling circuit, the mechanical pump component being driven by one transmission shaft of the driveline assembly. The transmission shaft can be a rotating shaft that drives an electric motor or speed reducer.

The written description is intended to disclose the embodiments of the disclosure, including the best mode, and to enable a person skilled in the art to make and use any device or system, and to perform any embodied method. An example is used to enable implementation. The patentable scope of the embodiments described herein is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples, if they have structural elements that do not differ from the literal language of the claims, or if they contain equivalent structural elements that do not differ substantially from the literal language of the claims, It is intended to be within the scope of the claims.

Claims (14)

A drive train system for an electric vehicle,
an electric motor comprising a rotor and a stator;
a power inverter configured to supply electrical energy to the stator;
a reduction gear comprising a transmission shaft configured to receive the torque provided by the rotor;
said electric motor, said power inverter and said speed reducer are integrated as a driveline assembly,
The driveline system comprises a cooling channel configured to flow a coolant and distribute the coolant throughout the driveline assembly, the cooling channel disposed within the power inverter; further comprises a cooling circuit comprising a coolant retention section for retaining said coolant from said cooling circuit, an inlet for receiving said coolant, and an outlet for discharging said coolant. , drivetrain system. 2. The driveline system of claim 1, further comprising a mechanical pump component connected to said cooling circuit, said mechanical pump component being driven by said transmission shaft to transfer said coolant to said cooling channel. an auxiliary heat transfer element is provided within the cooling channel;
3. The driveline system of claim 1 or 2, wherein the auxiliary heat transfer element comprises at least one spike, an extruded wall, or a combination thereof. a thermal mass provided with the electric motor, the speed reducer, or both;
The power inverter is mechanically attached to the electric motor, or the speed reducer, or both, thereby benefiting from the thermal mass to provide the cooling channel, as well as the coolant holding section and the thermal mass. 4. The driveline system of claim 3, wherein heat is dissipated therein via said coolant held within said auxiliary heat transfer element further increasing heat transfer to the body. cooling fins are provided on the outer surface of the electric motor, the speed reducer, or both the electric motor and the speed reducer;
The power inverter benefits from the cooling fins by being mechanically attached to the electric motor, or the speed reducer, or both, to the cooling channels and to the coolant holding section and the cooling fins. 4. The drivetrain system of claim 3, wherein heat is dissipated thereinto via said coolant held within said auxiliary heat transfer element further increasing heat transfer of said heat transfer element therein. said cooling channel configured as a loop formed along an inner peripheral edge of said power inverter;
2. The driveline system of claim 1, wherein said inlet and said outlet are positioned at an upper end of said cooling channel in a gravitational orientation. 2. The driveline system of claim 1, wherein the cooling channel is configured as a spiral-shaped channel, a serpentine-shaped channel, or a Z-shaped channel within the accommodation space of the power inverter. A method of cooling a driveline system for an electric vehicle comprising a driveline assembly integrated with an electric motor, a power inverter and a speed reducer, comprising:
providing a cooling circuit configured to flow a coolant and distribute the coolant throughout the drive train assembly;
providing the cooling circuit with a cooling channel located within the power inverter and further providing a coolant retention section for retaining coolant in the cooling channel. 4. The step of claim 1, further comprising providing a mechanical pump component connected to said cooling circuit, said mechanical pump component being driven by a transmission shaft of one of said drive train assemblies to transfer said coolant to said cooling channel. 8. The method according to 8. further comprising providing a supplemental heat transfer element within the cooling channel to facilitate thermal processing from the power inverter;
10. A method according to claim 8 or 9, wherein the auxiliary heat transfer element comprises at least one spike, an extruded wall, or a combination thereof. further comprising providing a thermal mass with the electric motor, the speed reducer, or both;
The power inverter benefits from the thermal mass by being mechanically attached to the electric motor, or the speed reducer, or both, to provide the cooling channel of the inverter, as well as the coolant holding section and 11. The method of claim 10, wherein heat is dissipated therein via the coolant retained in the auxiliary heat transfer element therein further increasing heat transfer to the thermal mass. further comprising providing cooling fins on an outer surface of the electric motor, the speed reducer, or both the electric motor and the speed reducer;
The power inverter benefits from the cooling fins by being mechanically attached to the electric motor, or the speed reducer, or both, so that the cooling channel of the inverter, as well as the coolant holding section and the 11. The method of claim 10, wherein heat is dissipated therein via the coolant retained in the auxiliary heat transfer element therein further increasing heat transfer to the cooling fins. forming the cooling channel as a loop along an inner peripheral edge of the power inverter;
9. The method of claim 8, further comprising locating the inlet and outlet of the cooling channel at the upper end of the cooling channel in a gravitational orientation. 9. The method of claim 8, further comprising forming the cooling channel as a spiral-shaped channel, a serpentine-shaped channel, or a Z-shaped channel within a receiving space of the power inverter.

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